The mission of the Southwest Oncology Group (SWOG) is to conduct clinical trials to prevent and treat cancer in adults, and to improve the quality of life for cancer survivors. The mission is accomplished through the mutual efforts ofthe Group Chair's Office, the Operations Office, the Statistical Center and the dedicated oncology professionals in the institutions of the Group. The Statistical Center contributes to the mission of the Group though the following key activities: 1) Participation in protocol development, emphasizing statistically sound study designs;2) Collection, review, manage and store data from Group studies, and to follow sound quality control procedures which ensure the integrity of data evaluations;3) Development and maintenance of electronic applications to support the research and goals of the Southwest Oncology Group, including data collection, data management, data retrieval and analysis;4) Analysis, interpretation and publication of results from ail Southwest Oncology Group studies;5) Performance of methodologic research to address ongoing design and analysis issues important to the conduct of cancer clinical trials and to ancillary biologic studies;6) Participation in training of new Clinical Research Associates (CRAs) and of Young Investigators in the Group. Biostatisticians and Data Coordinators educate investigators, nurse oncologists and CRAs in statistical analysis, research design and the utilization of the most advanced scientific and data management strategies;and 7) Collaboration with the Group Chair and other investigators in the Group to improve the quality of clinical trials through the use of improved data collection forms, reproducible data definitions and economical data flow, and efficient use of Statistical Center resources.